Charge exchange devices are critical components of tandem accelerator terminals, used widely in accelerator mass spectrometry, ion implantation, and other ion beam applications. These devices require the injection of negative ion beams and charge exchange in the center terminal, from which the positive ions emerge, gaining at least twice the energy of a single stage accelerator with the same terminal voltage (depending on the final charge state). Presently, existing techniques; foil stripping and gas stripping are greatly limited in their respective effectiveness. Foil stripping makes use of thin graphite foils, usually created by laser ablation. These foils are fragile and do not maintain their physical properties during ion bombardment. Their lifetime ranges from a few hours to at most a few days, depending on the ion beam parameters. Gas stripping introduces a degradation of the system beam line vacuum, unless complex differential pumping is employed. The degraded vacuum causes increased “background” events in the measured data. Gas stripping also requires the accelerator to be larger than it would have to be with foil stripping, as a low conductance stripper tube (0.5-1 m long) has to be fitted into the terminal.
Accordingly, there is a need in the art for improved devices, methods and materials for producing charged ions.